utag.ut.merge is not a function - what does it mean?

utag.ut.merge is an internal function in utag.js that's used to merge different objects together at different points in the page load.

You should never see the message you described. Although it's unlikely to be causing any major issues, I would recommend getting in touch with support (support@tealium.com) and letting us know which website/profile you are seeing this on so we can troubleshoot.